It is recommended to apply for a Schengen Visa from the US well in advance of your planned travel dates. The general rule is to submit your visa application no earlier than three months before your intended trip and no later than 15 calendar days before your departure. However, it is advisable to check the specific requirements and processing times of the consulate or embassy where you are applying, as some may have different timeframes or specific appointment availability.
Applying early allows for sufficient processing time, as the visa application process can take several weeks. It is also important to consider any additional time that may be required for collecting the necessary documents and making travel arrangements.
Keep in mind that it is not recommended to make any non-refundable travel arrangements, such as purchasing flight tickets or booking accommodation, until your visa has been approved and issued.